Great project John! I've been slowly working on customizing a Phantom for some time but had let it get pushed to the back burner recently. This thread has given me some great ideas and incentive to get back on it. I really like the laser idea - I was going to use a high intensity red LED but the laser is much better!
I picked up a cheap, unpainted Phantom shell and an F3 frame from Ebay a few years back and bought the Phantom 3 sound boards from Lionel. I am using a single DC power truck with traction tires I picked up in a box of junker parts at a swap meet. It's an odd power truck with the biggest DC can motor I've ever seen in an O-gauge train but it fits perfectly in the chassis and runs fine with the ERR CC board. I've never figured out what it actually came from.
For lighting effects I've also been thinking of adding colored EL wire in place of the steel rails (which were missing from this shell anyway).
Cheers,
Jim